Comparison of COVID-19 Incidence Rates Before and After School Reopening in Israel

This cohort study examines COVID-19 incidence rates in youths aged 0 to 19 before and after reopening schools in Israel.

Methods: 9,119 patients with SARS-CoV-2 infection received serial tests between December 1, 2019 and November 13, 2020 in 62 healthcare facilities in the United States. Reinfection was defined by 2 positive tests separated by >90 days after resolution of the first infection. Demographic and clinical characteristics associated with reinfection were identified. Limitations: Only included those with serial laboratory tests; persons receiving serial testing may not be representative of population at-risk; no sequence data for strains associated with reinfection.

Implications:
The low rate of reinfection with SARS-CoV-2 in the US seen here was similar to rates observed in France (0.47%) by Brouqui et al. Choudhary et al. suggests that reinfection may be due to waning SARS-CoV-2 antibodies or the presence of viral escape mutations. While reinfection appeared to be milder than primary infection, there was associated mortality. People who have recovered from SARS-CoV-2 infection should therefore continue with prevention measures such as social distancing, masking, and getting vaccinated.
Persistent symptoms the first few months following SARS-CoV-2 infection have been reported. As the pandemic progresses, new information concerning the type and longevity of continued symptoms, quality of life and development of COVID-19-associated conditions is emerging.
with minor symptoms who do not seek hospital care are not captured; database may be subject to information and misclassification errors.

Implications for both studies (Gautam et al. and Chevinsky et al.):
Patients with a history of COVID-19 may have persistent symptoms, in addition to general post-viral fatigue, that interfere with daily activities and negatively impact quality of life for months.

Methods:
Matched case-control observational study of 955 participants with HIV and 1062 participants without HIV conducted between August 1 and October 31, 2020. Remnant serum samples were tested for SARS-CoV-2 antibody concentrations and virus neutralization titer using a "pseudovirus" neutralization. Severe COVID-19 was assessed via chart review. Limitation: The SARS-CoV-2 IgG used in this study showed low sensitivity (89%); study did not report testing rates or test positivity, thus, data regarding current infections is limited.
Implications: People living with HIV were not at higher risk of SARS-CoV-2 infection than are those without HIV, however, the risk of severe COVID-19 after SARS-CoV-2 infection might be higher among people living with HIV. People living with HIV should be followed up after vaccination, to ensure they mount a sufficient immune response to prevent severe COVID-19.

PEER-REVIEWED
Physical inactivity is associated with a higher risk for severe COVID-

Methods:
Observational study using electronic health records from 48,440 adult COVID-19 Kaiser Permanente, Southern California patients (January and October 2020). Prior physical activity was categorized as consistently active/meeting physical activity guidelines (>150 min/week), some activity (11-149 min/week) and consistently inactive (0-10 min/week). Multivariable logistic regression model controlled for demographics and known risk factors. Limitations: Physical activity was self-reported; sparse data for adults who met the physical activity guidelines.
Implications: Regular physical activity may reduce the risk for severe COVID-19 outcomes among infected adults. Physical activity should be encouraged for many reasons, including to potentially reduce adverse COVID-19 outcomes.

PREPRINTS (NOT PEER-REVIEWED)
Efficacy of universal masking for source control and personal protection from simulated cough and exhaled aerosols in a room. Lindsley et al. medRxiv (April 25, 2021).

Key findings:
• Recipient aerosol exposure was reduced when source and recipient were both masked, separated up to 1.8 meters (~6 feet), and oriented front-to-front (92% decreased exposure when source was coughing, ≥66% during breathing) or side-to-side (≥78% when coughing and ≥76% during breathing) (Figure 1). • Changing source and recipient orientation from front-to-front to side-by-side reduced cough aerosol exposure by ≥59% when both were unmasked and separated up to 1.8 meters (Figure 1). • Increasing distance between unmasked source and recipients from 0.9 to 1.8 meters reduced recipient aerosol exposure by 25% when source was coughing.
Methods: A respiratory aerosol simulator ("source") and breathing simulator ("recipient") were used to determine how different combinations of masking, simulator orientations, and separation distance affected the aerosol exposure of the recipient (Figure 2). Limitations: Aerosol particles measured were from 0.3 to 3 μm, but humans produce particles across a broader size range.
Implications: Universal masking reduces exposure to respiratory aerosol particles regardless of the orientation and separation distance between the source and recipient. When both the source and recipient are unmasked, changes in orientation and separation distance can reduce recipient exposure.  In Brief